1.—Field of the Invention
The present disclosure relates generally to ultrasound imaging inside the living body and, in particular, to a focused intravascular ultrasound (IVUS) imaging catheter that produces high resolution intravascular imaging using a polymer based transducer.
2.—Description of Related Art
Intravascular ultrasound (IVUS) imaging is widely used in interventional cardiology as a diagnostic tool for a diseased vessel, such as an artery, within the human body to determine the need for treatment, to guide the intervention, and/or to assess its effectiveness. IVUS imaging uses ultrasound echoes to create an image of the vessel of interest. Ultrasound waves pass easily through most tissues and blood, but they are partially reflected from discontinuities arising from tissue structures (such as the various layers of the vessel wall), red blood cells, and other features of interest. The IVUS imaging system, which is connected to the IVUS catheter by way of a patient interface module (PIM), processes the received ultrasound echoes to produce a cross-sectional image of the vessel where the catheter is placed.
Current IVUS solutions do not provide resolution capable of differentiating structures without significant training in image interpretation. Structures requiring clearer images might include plaque burden, stent apposition, lipid pool identification, thrombus, and stent endothelization. While Optical Coherence Tomography (OCT) devices offer improved resolution, they require flushing to produce the image, and due to limitations of light penetration they do not allow for visualization of the vessel morphology beyond the surface of the vessel. While existing IVUS catheters deliver useful diagnostic information, there is a need for enhanced image quality to provide more valuable insight into the vessel condition. For further improvement in image quality in rotational IVUS, it is desirable to use a transducer with broader bandwidth and to incorporate focusing into the transducer.
What is needed is a method for high resolution ultrasound imaging to assess lesions, characterize vessels or to monitor other structures within a patient's body.